Question

(a) Is it possible to have two-level laser? If not, give comments.

(b) In a Ruby laser, the total number of Cr+

ions are 2.8 x 1019. If the laser emits radiation of

wavelength 700 nm, calculate energy of laser pulse.

(c) The output of a Ruby laser is not continuous. Comment and justify your answer​

Answer 1

Answer:

I don't know the answer sorry

Explanation:

sorrrrrrrrry

coming!

Answer 2

Answer:

• Laser action needs stimulated emission.
• Energy of laser pulse= total no. of ions(n) × energy of one photon(E).
• The output of a ruby laser is discontinuous.

Explanation: a) For any laser action, we need many energy levels and a metastable stage.

1. The two-level laser system has two energy levels but does not have a metastable stage.
2. When an atom moves from a lower energy state to the upper energy stage, its lifetime in the upper energy state is 10⁻⁸ seconds which is very short.
3. Due to this before population inversion occurs, there is spontaneous emission We know that for laser action stimulated emission is required not spontaneous emission.

b) Energy of laser pulse= total no. of ions(n) × energy of one photon

$E=nhc/lambda$

$n=2.8×10¹⁹\\h=6.62×10⁻³⁴J-s \\\\c=3×10⁸m/s\\lambda=7×10⁻⁷ A°$

$E=7.94 joules$

n=2.8×10¹⁹

h=6.62×10⁻³⁴J-s

c=3×10⁸m/s

∧=7×10⁻⁷ A°

n×h×c= 2.8×10¹⁹×6.62×10⁻³⁴×3×10⁸

∧= 7×10⁻⁷A°

E=nhc/lambda=7.94 joules

c) The output of a ruby laser is discontinuous and emits continuous pulses of visible light of a dark red colour. This is due to the movement of electrons in the crystal. Whenever electrons are provided with enough energy they move to the higher energy state and immediately return back to the lower state releasing a beam that is non-detectable.